Predicting the risk of cardiovascular disease in HIV-infected patients: the data collection on adverse effects of anti-HIV drugs study

AIMS

HIV-infected patients receiving combination antiretroviral therapy may experience metabolic complications, potentially increasing their risk of cardiovascular diseases (CVDs). Furthermore, exposures to some antiretroviral drugs seem to be independently associated with increased CVD risk. We aimed to develop cardiovascular risk-assessment models tailored to HIV-infected patients.

METHODS AND RESULTS

Prospective multinational cohort study. The data set included 22,625 HIV-infected patients from 20 countries in Europe and Australia who were free of CVD at entry into the Data collection on Adverse Effects of Anti-HIV Drugs Study. Using cross-validation methods, separate models were developed to predict the risk of myocardial infarction, coronary heart disease, and a composite CVD endpoint. Model performance was compared with the Framingham score. The models included age, sex, systolic blood pressure, smoking status, family history of CVD, diabetes, total cholesterol, HDL cholesterol and indinavir, lopinavir/r and abacavir exposure. The models performed well with area under the receiver operator curve statistics of 0.783 (range 0.642-0.820) for myocardial infarction, 0.776 (0.670-0.818) for coronary heart disease and 0.769 (0.695-0.824) for CVD. The models estimated more accurately the outcomes in the subgroups than the Framingham score.

CONCLUSION

Risk equations developed from a population of HIV-infected patients, incorporating routinely collected cardiovascular risk parameters and exposure to individual antiretroviral therapy drugs, might be more useful in estimating CVD risks in HIV-infected persons than conventional risk prediction models.

Boosted protease inhibitors and the electrocardiographic measures of QT and PR durations

BACKGROUND

There are contradictory reports regarding the effects of protease inhibitors on the ECG measures of QT and PR interval durations. The effect of interrupting use of protease inhibitors on QT and PR progression is also unknown.

METHODS

This analysis included 3719 participants from the Strategies for Management of Antiretroviral Therapy (SMART) study, of whom 1879 were randomized to receive intermittent antiretroviral therapy (ART) (drug conservation group), whereas the rest received these drugs continuously (viral suppression group). Linear regression analysis was used to compare four ritonavir-boosted protease inhibitor (protease inhibitor/r) regimens [saquinavir (SQV/r), lopinavir (LPV/r), atazanavir (ATV/r), and other protease inhibitor/r], and nonboosted protease inhibitor regimens with nonnucleoside reverse transcriptase inhibitor (NNRTI) regimens for Bazett's (QTcB) and Fredericia's (QTcF) heart rate corrected QT and PR. Changes in QTcB, QTcF, and PR after 12 and 24 months of randomization were compared in the drug conservation group and viral suppression group.

RESULTS

Average levels of QTcB, QTcF, and PR duration at entry were 415, 406, and 158 ms. At study entry, 49% of participants were taking an NNRTI (no protease inhibitor)-based regimen and 31% were prescribed a boosted protease inhibitor, the most common being LPV/r. After adjustment for baseline factors, QTcB and QTcF levels did not vary by boosted protease inhibitor group (P = 0.26 and P = 0.34, respectively). For those given any of the boosted protease inhibitors, QTcB was 1.5 ms lower than the NNRTI group (P = 0.04). Both boosted and nonboosted protease inhibitor-containing regimens were significantly associated (P < 0.01 for each) with longer PR intervals compared to the NNRTI group. After adjustment, the difference between boosted protease inhibitors and the NNRTI group was 5.11 ms (P < 0.01); for nonboosted protease inhibitors, this difference was 3.00 ms (P < 0.01). Following ART interruption, PR duration declined for both the boosted and nonboosted protease inhibitor groups and compared to the viral suppression group, significant changes in PR interval were observed 24 months after ART interruption of boosted protease inhibitors (P < 0.01).

CONCLUSION

Different protease inhibitor-based regimens have a similar, minimal effect on QT compared to NNRTI-based regimens. All protease inhibitor-based regimens (boosted and nonboosted) were associated with prolongation of PR, and interruption of protease inhibitor regimens reduced the prolonged PR duration. Further research is needed to confirm the findings of this study and assess the clinical relevance of the differences.

Cardiovascular implications from untreated human immunodeficiency virus infection

Atherosclerotic cardiovascular disease (CVD) has become an important cause of morbidity and mortality among individuals with human immunodeficiency virus (HIV) infection with access to antiretroviral medications, as the risk for AIDS has fallen and life expectancy improved. Traditional CVD risk factors are often more common among individuals with HIV infection, and traditional prevention strategies remain important. Recent data have revealed that untreated HIV infection itself amplifies additional pro-atherogenic mechanisms related to immune activation, inflammation, coagulation, and lipoprotein particle changes (e.g. high-density lipoprotein particles). Some of these mechanisms are attenuated, though incompletely, with antiretroviral therapy (ART)-related suppression of HIV replication. Exposure to ART is also associated with variable toxicity that may simultaneously decrease (via viral suppression) and increase CVD risk. Ultimately, additional adjunctive treatment will be needed to mitigate premature CVD risk among contemporary HIV-infected patients with access to ART.

Is it safe to discontinue primary Pneumocystis jiroveci pneumonia prophylaxis in patients with virologically suppressed HIV infection and a CD4 cell count <200 cells/microL?

BACKGROUND

Current guidelines suggest that primary prophylaxis for Pneumocystis jiroveci pneumonia (PcP) can be safely stopped in human immunodeficiency virus (HIV)-infected patients who are receiving combined antiretroviral therapy (cART) and who have a CD4 cell count >200 cells/microL. There are few data regarding the incidence of PcP or safety of stopping prophylaxis in virologically suppressed patients with CD4 cell counts of 101-200 cells/microL.

METHODS

The Opportunistic Infections Project Team of the Collaboration of Observational HIV Epidemiological Research in Europe (COHERE) included data from 23,412 patients from 12 European cohorts who started taking cART after 1997. Poisson regression was used to model incidence rate ratios (IRRs) of primary PcP.

RESULTS

There were 253 PcP cases during 107,016 person-years of follow-up (PYFU). Prophylaxis significantly reduced the incidence of PcP among patients with current CD4 cell counts 100 cells/microL (adjusted IRR, 0.41; 95% confidence interval [CI], 0.27-0.60) but not significantly among those with current CD4 cell counts of 101-200 cells/microL (adjusted IRR, 0.63; 95% CI, 0.34-1.17). The incidence of PcP among patients who had a current CD4 cell count of 100-200 cells/microL, who had a viral load <400 copies/mL, and who were receiving prophylaxis was 2.1 cases per 1000 PYFU (95% CI, 0.8-4.3 cases per 1000 PYFU; 7 events occurred during 3363 PYFU), whereas 1.2 cases per 1000 PYFU (95% CI, 0.2-4.5 cases per 1000 PYFU; 2 events occurred during 1614 PYFU) occurred among persons who were not receiving prophylaxis (adjusted IRR, 1.65; 95% CI, 0.33-8.15). Among patients who discontinued PcP prophylaxis after starting cART, the incidence of primary PcP was 0 cases per 1000 PYFU (95% CI, 0.0-2.7 cases per 1000 PYFU; 0 events occurred during 1363 PYFU) for patients who had a current CD4 cell count of 101-200 cells/microL and who were receiving cART.

CONCLUSIONS

The incidence of primary PcP among patients who had virologically suppressed HIV infection, were receiving cART, and who had CD4 cell counts >100 cells/microL was low irrespective of prophylaxis use. Discontinuation of prophylaxis may be safe in patients with CD4 counts of 101-200 cells/microL and suppressed viral load.

A comparison of the long-term durability of nevirapine, efavirenz and lopinavir in routine clinical practice in Europe: a EuroSIDA study

OBJECTIVES

The durability of combination antiretroviral therapy (cART) regimens can be measured as time to discontinuation because of toxicity or treatment failure, development of clinical disease or serious long-term adverse events. The aim of this analysis was to compare the durability of nevirapine, efavirenz and lopinavir regimens based on these measures.

METHODS

Patients starting a nevirapine, efavirenz or lopinavir-based cART regimen for the first time after 1 January 2000 were included in the analysis. Follow-up started ≥ 3 months after initiation of treatment if viral load was <500 HIV-1 RNA copies/mL. Durability was measured as discontinuation rate or development/worsening of clinical markers.

RESULTS

A total of 603 patients (21%) started nevirapine-based cART, 1465 (51%) efavirenz, and 818 (28%) lopinavir. After adjustment there was no significant difference in the risk of discontinuation for any reason between the groups on nevirapine and efavirenz (P=0.43) or lopinavir (P=0.13). Compared with the nevirapine group, those on efavirenz had a 48% (P=0.0002) and those on lopinavir a 63% (P<0.0001) lower risk of discontinuation because of treatment failure and a 31% (P=0.01) and 66% (P<.0001) higher risk, respectively, of discontinuation because of toxicities or patient/physician choice. There were no significant differences in the incidence of non-AIDS-related events, worsening anaemia, severe weight loss, increased aspartate aminotransferase (AST)/alanine aminotransferase (ALT) levels or increased total cholesterol. Compared with patients on nevirapine, those on lopinavir had an 80% higher incidence of high-density lipoprotein (HDL) cholesterol decreasing below 0.9 mmol/L (P=0.003), but there was no significant difference in this variable between those on nevirapine and those on efavirenz (P=0.39).

CONCLUSIONS

The long-term durability of nevirapine-based cART, based on risk of all-cause discontinuation and development of long-term adverse events, was comparable to that of efavirenz or lopinavir, in patients in routine clinical practice across Europe who initially tolerated and virologically responded to their regimen.

Estimated glomerular filtration rate, chronic kidney disease and antiretroviral drug use in HIV-positive patients

OBJECTIVES

Chronic kidney disease (CKD) in HIV-positive persons might be caused by both HIV and traditional or non-HIV-related factors. Our objective was to investigate long-term exposure to specific antiretroviral drugs and CKD.

DESIGN

A cohort study including 6843 HIV-positive persons with at least three serum creatinine measurements and corresponding body weight measurements from 2004 onwards.

METHODS

CKD was defined as either confirmed (two measurements >or=3 months apart) estimated glomerular filtration rate (eGFR) of 60 ml/min per 1.73 m or below for persons with baseline eGFR of above 60 ml/min per 1.73 m or confirmed 25% decline in eGFR for persons with baseline eGFR of 60 ml/min per 1.73 m or less, using the Cockcroft-Gault formula. Poisson regression was used to determine factors associated with CKD.

RESULTS

Two hundred and twenty-five (3.3%) persons progressed to CKD during 21 482 person-years follow-up, an incidence of 1.05 per 100 person-years follow-up [95% confidence interval (CI) 0.91-1.18]; median follow-up was 3.7 years (interquartile range 2.8-5.7). After adjustment for traditional factors associated with CKD and other confounding variables, increasing cumulative exposure to tenofovir [incidence rate ratio (IRR) per year 1.16, 95% CI 1.06-1.25, P < 0.0001), indinavir (IRR 1.12, 95% CI 1.06-1.18, P < 0.0001), atazanavir (IRR 1.21, 95% CI 1.09-1.34, P = 0.0003) and lopinavir/r (IRR 1.08, 95% CI 1.01-1.16, P = 0.030) were associated with a significantly increased rate of CKD. Consistent results were observed in wide-ranging sensitivity analyses, although of marginal statistical significance for lopinavir/r. No other antiretroviral drugs were associated with increased incidence of CKD.

CONCLUSION

In this nonrandomized large cohort, increasing exposure to tenofovir was associated with a higher incidence of CKD, as was true for indinavir and atazanavir, whereas the results for lopinavir/r were less clear.

Triple-class virologic failure in HIV-infected patients undergoing antiretroviral therapy for up to 10 years

BACKGROUND

Life expectancy of people with human immunodeficiency virus (HIV) is now estimated to approach that of the general population in some successfully treated subgroups. However, to attain these life expectancies, viral suppression must be maintained for decades.

METHODS

We studied the rate of triple-class virologic failure (TCVF) in patients within the Collaboration of Observational HIV Epidemiological Research Europe (COHERE) who started antiretroviral therapy (ART) that included a nonnucleoside reverse-transcriptase inhibitor (NNRTI) or a ritonavir-boosted protease inhibitor (PI/r) from 1998 onwards. We also focused on TCVF in patients who started a PI/r-containing regimen after a first-line NNRTI-containing regimen failed.

RESULTS

Of 45 937 patients followed up for a median (interquartile range) of 3.0 (1.5-5.0) years, 980 developed TCVF (2.1%). By 5 and 9 years after starting ART, an estimated 3.4% (95% confidence interval [CI], 3.1%-3.6%) and 8.6% (95% CI, 7.5%-9.8%) of patients, respectively, had developed TCVF. The incidence of TCVF rose during the first 3 to 4 years on ART but plateaued thereafter. There was no significant difference in the risk of TCVF according to whether the initial regimen was NNRTI or PI/r based (P = .11). By 5 years after starting a PI/r regimen as second-line therapy, 46% of patients had developed TCVF.

CONCLUSIONS

The rate of virologic failure of the 3 original drug classes is low, but not negligible, and does not appear to diminish over time from starting ART. If this trend continues, many patients are likely to need newer drugs to maintain viral suppression. The rate of TCVF from the start of a PI/r regimen after NNRTI failure provides a comparator for studies of response to second-line regimens in resource-limited settings.

History of viral suppression on combination antiretroviral therapy as a predictor of virological failure after a treatment change

OBJECTIVES

HIV-infected persons experience different patterns of viral suppression after initiating combination antiretroviral therapy (cART). The relationship between such differences and risk of virological failure after starting a new antiretroviral could help with patient monitoring strategies.

METHODS

A total of 1827 patients on cART starting at least one new antiretroviral from 1 January 2000 while maintaining a suppressed viral load were included in the analysis. Poisson regression analysis identified factors predictive of virological failure after baseline in addition to traditional demographic variables. Baseline was defined as the date of starting new antiretrovirals.

RESULTS

Four hundred and fifty-one patients (24.7%) experienced virological failure, with an incidence rate (IR) of 7.3 per 100 person-years of follow-up (PYFU) [95% confidence interval (CI) 6.7-8.0]. After adjustment, patients who had rebounded in the year prior to baseline had a 2.4-times higher rate of virological failure after baseline (95% CI 1.77-3.26; P<.0001), while there was no increased incidence in patients whose last viral rebound was >3 years prior to baseline [Incidence rate ratio (IRR) 1.06; 95% CI 0.75-1.50; P=0.73] compared with patients who had never virally rebounded. Patients had an 86% (95% CI 1.36-2.55; P<.0001), 53% (95% CI 1.06-2.04; P=0.02) and 5% (95% CI 0.80-1.38; P=0.72) higher virological failure rate after baseline if they were virally suppressed <50%, 50-70% and 70-90% of the time they were on cART prior to baseline, respectively, compared with those virally suppressed >90% of the time.

DISCUSSION

Intensive monitoring after a treatment switch is required in patients who have rebounded recently or have a low percentage of time suppressed while on cART. Consideration should be given to increasing the provision of adherence counselling.

A biobehavioural model of the night eating syndrome

This paper will propose a biobehavioral mechanism for the Night Eating Syndrome (NES), a disorder characterized by a delayed circadian rhythm of food intake and neuroendocrine function. Food intake consists of at least 25% of daily caloric intake after the evening meal and/or at least two nighttime awakenings with ingestions per week. This will be explored by reviewing neuroimaging of brain serotonin transporters (SERT) and treatment with selective serotonin reuptake inhibitors (SSRIs). SERT binding is elevated in the midbrain of night eaters, causing dysregulation of the circadian rhythm of both food intake and neuroendocrine function. The administration of SSRIs blocks the reuptake of serotonin and restores the circadian rhythm of both food intake and neuroendocrine function. This hypothesis implies that reduction of SERT activity should increase postsynaptic serotonin transmission and relieve NES. This is precisely the effect of SSRIs. NES is a function of elevated SERT, and blocking of SERT with an SSRI resolves NES. This model of NES attests to the validity of the diagnosis of NES and the criteria by which it is identified, and it provides an explanation of the mechanism.

Interleukin-2 therapy in patients with HIV infection

BACKGROUND

Used in combination with antiretroviral therapy, subcutaneous recombinant interleukin-2 raises CD4+ cell counts more than does antiretroviral therapy alone. The clinical implication of these increases is not known.

METHODS

We conducted two trials: the Subcutaneous Recombinant, Human Interleukin-2 in HIV-Infected Patients with Low CD4+ Counts under Active Antiretroviral Therapy (SILCAAT) study and the Evaluation of Subcutaneous Proleukin in a Randomized International Trial (ESPRIT). In each, patients infected with the human immunodeficiency virus (HIV) who had CD4+ cell counts of either 50 to 299 per cubic millimeter (SILCAAT) or 300 or more per cubic millimeter (ESPRIT) were randomly assigned to receive interleukin-2 plus antiretroviral therapy or antiretroviral therapy alone. The interleukin-2 regimen consisted of cycles of 5 consecutive days each, administered at 8-week intervals. The SILCAAT study involved six cycles and a dose of 4.5 million IU of interleukin-2 twice daily; ESPRIT involved three cycles and a dose of 7.5 million IU twice daily. Additional cycles were recommended to maintain the CD4+ cell count above predefined target levels. The primary end point of both studies was opportunistic disease or death from any cause.

RESULTS

In the SILCAAT study, 1695 patients (849 receiving interleukin-2 plus antiretroviral therapy and 846 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 202 cells per cubic millimeter were enrolled; in ESPRIT, 4111 patients (2071 receiving interleukin-2 plus antiretroviral therapy and 2040 receiving antiretroviral therapy alone) who had a median CD4+ cell count of 457 cells per cubic millimeter were enrolled. Over a median follow-up period of 7 to 8 years, the CD4+ cell count was higher in the interleukin-2 group than in the group receiving antiretroviral therapy alone--by 53 and 159 cells per cubic millimeter, on average, in the SILCAAT study and ESPRIT, respectively. Hazard ratios for opportunistic disease or death from any cause with interleukin-2 plus antiretroviral therapy (vs. antiretroviral therapy alone) were 0.91 (95% confidence interval [CI], 0.70 to 1.18; P=0.47) in the SILCAAT study and 0.94 (95% CI, 0.75 to 1.16; P=0.55) in ESPRIT. The hazard ratios for death from any cause and for grade 4 clinical events were 1.06 (P=0.73) and 1.10 (P=0.35), respectively, in the SILCAAT study and 0.90 (P=0.42) and 1.23 (P=0.003), respectively, in ESPRIT.

CONCLUSIONS

Despite a substantial and sustained increase in the CD4+ cell count, as compared with antiretroviral therapy alone, interleukin-2 plus antiretroviral therapy yielded no clinical benefit in either study. (ClinicalTrials.gov numbers, NCT00004978 [ESPRIT] and NCT00013611 [SILCAAT study].)

Activation and coagulation biomarkers are independent predictors of the development of opportunistic disease in patients with HIV infection

BACKGROUND

Activation and coagulation biomarkers were measured within the Strategies for Management of Antiretroviral Therapy (SMART) trial. Their associations with opportunistic disease (OD) in human immunodeficiency virus (HIV)-positive patients were examined.

METHODS

Inflammatory (high-sensitivity C-reactive protein [hsCRP], interleukin-6 [IL-6], amyloid-A, and amyloid-P) and coagulation (D-dimer and prothrombin-fragment 1+2) markers were determined. Conditional logistic regression analyses were used to assess associations between these biomarkers and risk of OD.

RESULTS

The 91 patients who developed an OD were matched to 182 control subjects. Patients with an hsCRP level > or =5 microg/mL at baseline had a 3.5 higher odds of OD (95% confidence interval [CI], 1.5-8.1) than did those with an hsCRP level <1 microg/mL (P=.003, by test for trend) and patients with an IL-6 level > or =3 pg/mL at baseline had a 2.4 higher odds of OD (95% CI, 1.0-5.4) than did those with an IL-6 level <1.5 pg/mL (P=.02, by test for trend). No other baseline biomarkers predicted development of an OD. Latest follow-up hsCRP level for those with an hsCRP level > or =5 microg/mL (compared with a level <1 microg/mL; odds ratio [OR], 7.6; 95% CI, 2.0-28.5; [P=.002, by test for trend), latest amyloid-A level for those with an amyloid-A level > or =6 mg/L (compared with a level <2 mg/L; OR, 3.8; 95% CI, 1.1-13.4; P=.03, by test for trend), and latest IL-6 level for those with an IL-6 level > or =3 pg/mL (compared with a level <1.5 pg/mL; OR 2.4; 95% CI, 0.7-8.8; P=.04, by test for trend) were also associated with development of an OD.

CONCLUSIONS

Higher IL-6 and hsCRP levels independently predicted development of OD. These biomarkers could provide additional prognostic information for predicting the risk of OD.

Genetic evolution of HIV in patients remaining on a stable HAART regimen despite insufficient viral suppression

Our objective was to investigate whether steadily increasing resistance levels are inevitable in the course of a failing but unchanged Highly Active Antiretroviral Therapy (HAART) regimen. Patients having an unchanged HAART regimen and a good CD4 response (100 cells/microl above nadir) despite consistent HIV-RNA levels above 200 copies/ml were included in the study. The study period spanned at least 12 months and included 47 plasma samples from 17 patients that were sequenced and analysed with respect to evolutionary changes. At inclusion, the median CD4 count was 300 cells/ml (inter-quartile range (IQR): 231-380) and the median HIV-RNA was 2000 copies/ml (IQR: 1301-6090). Reverse transcription inhibitor (RTI) mutations increased 0.5 mutations per y (STD = 0.8 mutations per y), while major protease inhibitor (PI) resistance mutations increased at a rate of 0.2 mutations per y (STD = 0.8 mutations per y) and minor PI resistance mutations increased at a rate of 0.3 mutations per y (STD = 0.7 mutations per y). The rate at which RTI mutations accumulated decreased during the study period (p = 0.035). Interestingly, the rate of mutation accumulation was not associated with HIV-RNA level. The majority of patients kept accumulating new resistance mutations. However, 3 out of 17 patients with viral failure were caught in an apparent mutational deadlock, thus the development of additional resistance during a failing HAART is not inevitable. We hypothesize that certain patterns of mutations can cause a mutational deadlock where the evolutionary benefit of further resistance mutation is limited if the patient is kept on a stable HAART regimen.

Limited but increasing use of treatment for hepatitis C across Europe in patients coinfected with HIV and hepatitis C

Uptake of hepatitis C (HCV) treatment in HIV-coinfected patients is not well described. Of 2356 HCV-seropositive patients, 180 (7.6%) started HCV treatment with interferon-based therapies. In multivariate Poisson-regression models, there was a 38% increase per year in the incidence of starting HCV treatment (95% CI 26 - 51%, p<0.0001); this increased from 3.9 per 1000 person-years follow-up (PYFU) before 1998 (95% CI 1.6 - 6.1) to 32.6 per 1000 PYFU at/after 2004 (95% CI 22.5 - 42.7). Although prescription of HCV therapy is increasing in HIV-coinfected patients, it remains infrequent and variable across regions of Europe.

[Major breakthroughs in the medical treatment]

The introduction of antiretroviral combination therapy for patients with HIV infection is described as an example of a breakthrough within the field of medical treatment. The background for the breakthrough and the phases thereof are described and for comparison, the circumstances of major breakthroughs within other medical specialities are mentioned.